Dust Down Under
Posted September 26, 2009
You probably saw the mentions of a major dust storm over eastern Australia this week, but may not have seen some of the images of the event as seen from above and within. I've attached a couple of shots from NASA's Terra and Aqua satellites.
The first, taken on Wednesday, Sept. 23, clearly show strong winds lofting billows of dust from a lengthy series of source areas, reportedly drought-stricken and un-planted fields, with a sharp "dust front" that remains a little inland over the state of Queensland, but has already moved offshore from New South Wales. Reports from the area indicate that particulate concentrations in the air increased from typical levels of 10-20 micrograms per cubic meter to over 15,000 in some areas.
By the next day (2nd image), the dust band has moved out to sea, and the Australian surface is again seen crisply and clearly from the satellite, except for a couple of areas where large fires are producing smoke plumes. The NASA site hosting the images notes that the band of dust stretches northwest to southeast for about 2,300 miles, not all visible in this shot. That's about the distance from New York to Los Angeles!
To get a feel for what it was like within the plume, you can type "Sydney dust" or "Australia dust" into a search engine and turn up numerous photo galleries. I added one Reuters photo of a fellow walking under the Sydney Harbor Bridge as a sample. Some of the images are quite beautiful and eerie.
See the link to NASA's Earth Observatory site for more discussion of the images.